A Look Inside Apple’s Custom GPU for the iPhone

I am not in a position to comment a lot of things about GPUs since I lack the knowledge, however I am a little bit skeptical about a lot of the remarks that you are making on the second half of the article concerning the benefits of using custom hardware.

Since Apple controls both the system software and hardware for its devices, it is apparently far easier to innovate certain aspects or make far deeper optimizations than others who do not exercise control on both components can do. However it is not all rosy in the custom-do-it-all-by-yourself side of things.

For a company the size of Apple, I believe that it can command any supplier for specific features and be the first to use (and maybe the only). This is custom design services. What you are saying about a benefit for Apple could then become a benefit for competitors is a possibility but there are two factors to consider: (i) when will this happen? If Apple benefits in generation n and the competitors in generation (n+1) then Apple still is far ahead, (ii) Apple from your writing will benefit the most from the combination of software + hardware, so even if the hardware benefits trickle down to competitors, I am not sure they can benefit.

Further more, one of your arguments about debugging and reacting to bugs, I think that it is far easier to locate and correct bugs when multiple companies are looking at the same problem (from different perspectives and use cases) than a single company can do. In the case of debugging and using an error-free design (if such a thing exists), the more the better. I am not sure it works with the timings - you may be right that it will take more to correct a third-party IP than an in-house, but again I am not sure about that.

Now concerning time to market, I think that traditionally the argument about using third-party IP is exactly that: you can design faster by using the work that someone else has already completed and verified. With Apple commanding such a high volume of Imagination's business, do you think that if Apple sends them a request to fix a bug, it will be priority #1 or something else?

There is also another thing that you need to consider. And this is risk. What if Apple discovers that its new design has a fault, is inadequate, bad manufacturability etc? This is the big risk with doing custom work and statistically checking the competitive landscape, all manufacturers have been hit by it. Apple can manage to hide it under the carpet since it controls all the stack and that is a big bonus. But the risk is still there.